The synthesis of messenger RNA precursors by RNA polymerase II is the primary event in gene expression and is central to the life of cells. The amount of mRNA made from each gene is a key determinant of how much of each corresponding protein is made. For this reason RNA pol II function is extremely carefully regulated by the cell. Corruption of this process of transcription is a major cause of cancer and interference with the transcription program of viruses is a potential target for therapeutics. Transcription can be regulated at the level of initiation of the RNA chains or at the level of their elongation. Initiation is thought to be regulated by controlling recruitment of RNA polymerase to a gene's promoter region but it is much less clear how elongation is controlled. Elongational control is important in a number of clinically important examples. HIV regulates its transcription at the level of elongation and failure to regulate elongation of c-myc oncogene transcripts contributes to development of Burkitt's lymphoma. In this proposal, genetic and biochemical approaches will be used to study pol II transcriptional elongation and termination in animal cells and in budding yeast. The proteins of the transcriptional machinery are highly conserved between yeast and mammals and yeast offers significant experimental advantages for genetics. The specific aims of this work are: Aim 1: To determine how elongation factors influence transcription and termination by pol II on individual genes in budding yeast. Aim 2: To determine the role of the pol II CTD in termination of transcription at the 3' ends of genes encoding polyadenylated and non-polyadenylated RNAs. Aim 3: To determine how pre-mRNA processing factors that associate with transcribing pol II affect elongation and termination at genes that produce polyadenylated and non-polyadenylated transcripts. [unreadable] [unreadable]